Process of purifying



basic slag.

lTED STATES PATENT i FFIQE'.

BENJAMIN 'IALBOT, OF CI-IATTANOOGA, TENNESSEE.

success or on marine METALS.

SPEOIFIQA'I'ION forming part of Letters Patent No. 476,091, dated May 31, 1892. Apnlicetion filed January 19, 1892- Serlal Ho. 418,583. (No specimens.)

To all whom it" may concern: a

Be it known thatl, BENJAMIN TALBOT, a resident of Chattanooga, Hamilton county, Tennessee, formerly a subjectof Great Britain, but having declared my intention of becoming a citizen of the United States, havh'invented certain new and useful Improvements in the Process of Purifying Metals, of which the following is a specification.

Myinvention relates to the art of purifying iron in particular, although it is,- i believe, applicable to the treatment of other metals, and has in View as its principal object the elimination of silicon.

My process is a filtration process carried on outside of the furnace or melting-chamher and is based on the fact that if liquid pig iron containing impurities is brought into contact with liquid basic slag a reaction occurs, and so long as oxide of iron continues in the slag and the base is in excess the impurities are transferred from the metal to the slag and metallic iron is reduced from theslag and takes the place of the expelled impurities. The reaction that occurs during the operation is of a very active character, and its effect is not only to maintain but in some cases to raise the temperature of the It is this fact which enables me to carry on my filtration process of purification outside of the furnace and in a continuing manner. in conducting the operation, there will be, in

weight, considerably more of the purified than of the impure metal at the beginthis consequence of the transierenoe oi the metal from the basic slag.

in applying any process to the treatment of notably silicious pi iron such, for instance, as those made in the State of Alabama-d prefer to proceed as follows: In a regenerative gasiurnace I make a basic slag consist- Oif OXldG of iron and lime mixed. 1 melt this at a very high temperature in order to get it extremely hot and limpid and have it in its most effective basic condition. I pour this slag at its high temperature into a suit/- able vessel, so that a deep body or column is nuiintained it will remain in a fluid condition Without the application of external heat.

The metal to be purified, as cast-iron, is ohif there is no mechanical loss tained from the blast-furnace or elsewhere and-is poured from above into the column of slag, through which it sinks by reason of its superior gravity to the bottom, where it ac cumulates. It is found that in its passage through the slag the metalis desiliconized,

so that it arrives and accumulates at the bottom in a purified condition,o'ther foreign matters than the silicon being also incidentally removed to a considerable extent.

The bath or column of liquid slag should be of considerable dept-h, an increase of depth within reasonable limits being attended with advantage. The reactions occurring during the process are of such character as to maintain the temperature and admit of the operation being carried on continuously and for a long period of time without application of heat from an external source.

At the bottom of the vessel I provide a taphole, through which the purified metal is withdrawn into another vess lwhile impure metal is being run in at the top, and in this way I am enabled to make the process acontinuous one. Care should be taken that the metal is .poured into the top as fast or a little faster than it is run out at the bottom, to the end that there may be. no escape of'the slag.

The process is very rapid and practically instantaneous. The silicon is eliminated from the iron, and as metallic iron takes the place of the impurities expelled there is no waste. The refined iron may be transferred to the basic open-hearth furnace, so that it can be further purified and the temperature raised, so that the best quality of low-phosphorous steel can be obtained and cast into ingots Without skulling. ll arrange the composition of my according to the character of the work to be done. If I desire only to desilioouiz-e without eliminating materially the carbon or phosphoruai put into the-slag only so much oxide of iron as will be exhausted by the time it has expelled the sili; con from the metal. As soon as this occurs the reaction ceaseaas there is no oxygen left for the work.

in plants where steel-making is carried on by the basic process I propose to utilize the waste basic slag of the process by running through it "While in its original liquid condiverter or' furnace which produced the basic slag; The result of the treatment of the castiron by the basic slag from the furnace is n metnl low in silicon and more or less reduced in carbon and phosphorus and well consti tuted to go to the basicconverter or furnace for complete dephos'phorizetion. In thus utilizing the waste slug from the basic process 'I propose to transfer it at once and while in its original fluid state to a suitable vessel in which it may be meinteined in a. deep hotly or column and to pour the liquid motel down through it in the manner heretofore explained.

in practice it is found that by bringing the liquid metal and the liquid slag into cont-act by n filtration process, as herein described, with u deep column orbody ot' slug ism enabled to secure their thorough and intimate contact in all their parts, and thus toinsure a; re idity and uniformity of purification whic cannot be otherwise obtuined.

If complete purification is desired, so that practically an the in] purities will be removed, I find than; the best results are obtained by subdividing or breaking up the iiuid iron into a. series of small strcnmsnnd allowing itto full in this form into and through the slug, this subdivision being attended with an increased exposure of surface to the slug nnd resulting in a more rapid completion of the process.

Metal of the same composition as muckbnr may in this manner he obtnined.--tii-' rectly from the crude iron.

the purified motel from the slag.

the slug.

i cruoei I claim is" A 1, The process of purifying iron,which consists in placing in n suitnble vessel e deep column of liquid basic slug, pouringthe molten iron downward through the stag, thereby cone in g the rnetelloids and other impurities toco rnfbine with the basic elements of the slag, the reaction liberating bent, whereby the slag is maintained in a. fluid stnte, continuing the pouring of impure inetul through the slug, end

separating-the purified metal from the slug.

2. Theprocess of purifying iron, which con= sists in treating iron by the basic process, removing the resulting basic slug to e vessel constructed to hold a, deep column of the slug, pouring molten iron to be purified downward basic elements of the slug, the renction libernting bent, whereby the slag is maintained in n fluid stute, continuing the pouring of impure metal through the slug, and separating 3, Theprocess of pnrifyingiron, u'hichcbw sists in placing in a suitable vessel e dcepoole. unm of liquid basic slug, pouring the moiteniron downward through the slug, thereby cutieing the metslloitls or other iinpuritiesto corn-I bine with the basic elements of the slng t thej,

reaction liberating heat, whereby the slng fis maintained in n, fluid state, continuing-the pour-ingot impure metal through the slug, end Withdrawing the purified metal from below BENJAMIN Tensor,- Witnesses.- P

J. W. Sun, JAS FITTQN.

vthrough the slng,-thereby cunning the metalloids or otherimpurities to combine with the 

